The purposes of this randomized controlled trial are to test the effectiveness of Freedom from Radon Exposure and Smoking in the Home (FRESH), a dual home screening and tailored environmental feedback intervention designed to reduce environmental risks for lung cancer, and to identify factors associated with monetary incentives for radon mitigation. The combination of firsthand smoke, secondhand smoke (SHS), and radon exposure increases the risk of lung cancer nearly tenfold. The long-term goals are to foster environmental justice by reducing home exposure to radon and SHS and to promote equity in radon mitigation by policy change to provide tax credits. A randomized controlled trial enrolling 550 primary care patients will test four hypotheses, controlling for contextual factors of age, gender, home smoking, and socioeconomic status (SES): 1) Those who receive FRESH will be more likely to take action to test and mitigate for radon and institute and enforce a smoke-free home policy compared to the control group; 2) Those receiving FRESH will have lower radon and home SHS levels at 15 months post-intervention compared to the control group; 3) Those who receive FRESH will have greater increases in perceived risk of lung cancer and synergistic risk perception (SHS x radon), health-related self-concept, readiness to change, and self-efficacy to prevent lung cancer, and a greater decrease in lung cancer worry compared to controls at 15 months post-intervention; and 4) Those with at least one smoker in the home will be less likely to take action to reduce exposure to radon and SHS. The Treatment group (n = 275) will receive free test kits in the primary care clinic to measure their homes for radon and SHS at baseline, receive their test results and the tailored environmental feedback intervention, and take part in baseline and three follow up online surveys and home testing 15 months post-intervention. Those with high radon will receive a voucher for 30% of the cost up to $600 for radon mitigation. The Control group (n = 275) will receive information on how to request test kits for radon and SHS and a brochure on radon and SHS, and take part in all study surveys. Participants in both groups will be asked to test their homes for radon and SHS 15 months post-intervention. Project The proposal is directly relevant to public health in that it has the potential to prevent lung cancer by reducing exposure to radon and secondhand smoke in the home.